1. Field Of The Invention
The invention relates to a method and device for trimming grinding wheels, advantageously by means of a diamond trimming wheel, on grinding machines. The invention also relates to a device for accomplishing the method.
2. Description Of The Prior Art
Customarily in the manufacturing of mechanical devices, particularly precision mechanical devices where it is desired to produce workpieces with fine dimensional tolerances and finely ground surfaces, the grinding step or steps is/are carried out on a grinding machine wherein the workpiece to be ground is held on a rotary table, disposed on the turning slide, between headstock and a tailstock. The turning slide is translatable along the longitudinal axis (Z-axis) of the grinding machine. In addition, the rotary table can be rotated with respect to the turning slide around a vertical axis (B-axis) of the grinding machine, such that the workpiece spinnably held along the axis defined by the headstock and tailstock (the C-axis) is three dimensionally positionable with respect to the grinding wheel, which wheel is spinnable around its own rotational axis (A-axis) and is translatable along an additional axis (X-axis). Customarily, on such a grinding machine, which advantageously is numerically controlled (NC), the trimming wheel for the grinding wheel is mounted on the rotary table, such that said trimming wheel can advantageously be spun around the aforementioned C-axis around which the workpiece is rotated. Because when the movable slide is rotated around the aforesaid B-axis (whereby the C-axis is rotated around the B-axis) the C-axis is rotated away from the longitudinal axis (Z-axis) of the grinding machine, the grinding line between the grinding wheel and the trimming wheel may be spatially positioned as desired. While this freedom can be advantageous, it carries the drawback that the relation between the G-T grinding line (grinding line between grinding wheel and trimming wheel) and the G-W grinding line (grinding line between grinding wheel and workpiece) is not (or not always) directly calculable and must be re-zeroed after each trimming step in order to accurately determine the new position of the G-W grinding line. In addition, the position of the trimming wheel, which wheel customarily remains mounted on the turning slide during the grinding of a workpiece, is rotated, with respect to the grinding wheel, by each rotation of the turning slide as well as by the zeroing of the C-axis; and this necessitates a new zeroing of the trimming wheel prior to each trimming step.